// 动画库
@-webkit-keyframes slideInUp {
  from {
    bottom: -8rem;
    visibility: visible;
  }

  to {
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
  }
}

@keyframes slideInUp {
  from {
    bottom: -8rem;
    visibility: visible;
  }

  to {
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
  }
}

.slideInUp {
  -webkit-animation-name: slideInUp;
  animation-name: slideInUp;
}

@-webkit-keyframes slideOutDown {
  from {
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
  }

  to {
    visibility: hidden;
    bottom: -8rem;
  }
}

@keyframes slideOutDown {
  from {
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
  }

  to {
    visibility: hidden;
    bottom: -8rem;
  }
}

.slideOutDown {
  -webkit-animation-name: slideOutDown;
  animation-name: slideOutDown;
}

// 置顶按钮
#top_btn {
  position: absolute;
  position: fixed;
  bottom: .8rem;
  right: .8rem;
  width: 3.5rem;
  height: 3.5rem;
  border-radius: 10rem;
  font-size: 1.8rem;
  line-height: 3.5rem;
  text-align: center;
  color: rgba(0, 0, 0, 0.6);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  cursor: pointer;
  background-color: #fdc223;
  z-index: 999;
  @media (min-width: 960px) {
    width: 4rem;
    height: 4rem;
    margin: 2.5rem;
    line-height: 4rem;
    bottom: 0.5rem;
    right: 0.5rem;
  }
  display: none;
  animation-duration: 0.6s;
  animation-fill-mode: both;
}
